27.3. Input Resistance Analysis

Try these first

1. 1.

   What is the relationship between input resistance and loading effect?

   Hint

   Think about how much the amplifier takes away from the incoming signal.

2. 2.

   Define output resistance.

   Hint

   Consider what an amplifier presents to the load connected to it.

3. 3.

   What does high input resistance in an amplifier indicate?

   • Increased loading
   • Decreased loading
   • No effect

   Hint

   Remember the importance of loading effects on signal integrity.

4. 4.

   True or False: The presence of R_E increases the overall voltage gain in a common emitter amplifier.

   • True
   • False

   Hint

   Think about the trade-off with stability.

5. 5.

   Derive the full small signal equivalent model for a common emitter amplifier with an emitter resistor considering all contributing resistances.

   Hint

   Use your knowledge of small-signal modeling; start from the basic transistor model.

6. 6.

   Given a common emitter amplifier configuration with specific values for R_C, R_E, and beta, calculate the expected input and output resistances.

   Hint

   Identify each component's contribution to overall resistance.